Your post makes no sense, but your choice. Colin advises not to dual boot
XP and Vista because the Restore Points in Vista are deleted each time you
boot into XP. So, how many times have you used system restore, and how many
times has it worked. If you have another method of restoring in an
emergency, it may be worth it to run programs that won't run in Vista but
which you aren't ready or can't replace yet. For most people, I fully agree
and his warning should be heeded. Colin likes virtual machines and that may
very well be the way for some or even you to go.
Why would you be running Partition Magic at all, when you know it doesn't
work with Vista? What I suggested does not require any use of PM. Why
would you take any advice from Symantec, let alone from some junior flunky
who punches a few keywords in the computer and reads back the output, but
who probably knows nothing about partitioning. You would not be
partitioning your C drive. You would be creating two or more partitions on
a hard drive. (one may be CO, on the other hand it may be a different
letter in each system you boot into).
Good luck.